mirror of https://gitlab.com/QEF/q-e.git
65 lines
1.6 KiB
Fortran
65 lines
1.6 KiB
Fortran
!
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! Copyright (C) 2001 PWSCF group
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! This file is distributed under the terms of the
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! GNU General Public License. See the file `License'
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! in the root directory of the present distribution,
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! or http://www.gnu.org/copyleft/gpl.txt .
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!
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!
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!-----------------------------------------------------------------------
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subroutine sym_elop (phi, nsym, s, nat, irt)
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!-----------------------------------------------------------------------
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!
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! Symmetrizes the Electr-optic tensor
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! The tensor in input is a real tensor in crystal coordinates.
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!
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#include "f_defs.h"
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use kinds, only : DP
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implicit none
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integer :: nsym, s (3, 3, 48), nat, irt (48, nat)
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! input: the number of symmetries
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! input: the rotation matrix
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! input: the number of atoms
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! input: correspondence between rotated atoms
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real(DP) :: phi (3, 3, 3)
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! matrix to symmetrize
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integer :: isym, i, j, k, l, m, n, na, sna
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! counter on symmetries
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! counter on axis
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! counter on atoms
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! the rotated atom
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real(DP) :: work (3, 3, 3)
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! auxiliary space
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if (nsym.eq.1) return
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work (:,:,:) = 0.d0
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do isym = 1, nsym
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do i = 1, 3
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do j = 1, 3
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do k = 1, 3
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do l = 1, 3
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do m = 1, 3
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do n = 1, 3
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work (i, j, k) = work (i, j, k) + &
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s (i, l, isym) * &
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s (j, m, isym) * &
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s (k, n, isym) * phi (l, m, n)
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enddo
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enddo
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enddo
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enddo
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enddo
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enddo
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enddo
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call DSCAL (27, 1.d0 / DBLE (nsym), work, 1)
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call DCOPY (27, work, 1, phi, 1)
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return
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end subroutine sym_elop
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